1. Field of the Invention
The invention relates to an ink-jet head, and particularly to an ink-jet head in which a plurality of pressure chambers are arranged in a matrix to neighbor each other.
2. Description of Related Art
There is known a type of ink-jet head in which ink is ejected through a nozzle communicating with each pressure chamber when pressure is applied by a piezoelectric element to the ink in each of the pressure chambers arranged in one or two rows in an in-line shape. The ink-jet head is manufactured by laminating a plurality of plates. Generally, the pressure chambers are formed by a single plate having holes being sandwiched from both faces thereof by other plates, respectively.
Accordingly, in case of bonding a plurality of plates constituting the pressure chambers to each other with an adhesive, the adhesive applied to interfaces of the plates flows into the holes during a manufacturing process of the ink-jet head, and as a result, a shape of the pressure chamber is changed. Such a phenomenon occurs particularly for pressure chambers disposed on both ends of a row, among a plurality of pressure chambers arranged in one or two rows, because there is not formed any hole for a pressure chamber on one side of each of the pressure chambers disposed on both ends of a row. Further, among the plurality of pressure chambers thus arranged, the pressure chambers disposed on both ends of a row are different from the other pressure chambers in bending amount of sidewalls thereof due to a difference in thickness of the sidewalls. Like this, a difference in a shape of pressure chambers due to a flowed-in adhesive and a difference in a bending amount of side walls of pressure chambers are caused between the pressure chambers disposed on both ends of a row and the other pressure chambers, among a plurality of pressure chambers arranged in one or two rows, thereby causing a difference in ink ejecting characteristics. To solve this problem, there is known a technique to provide pressure chambers performing no ink ejection, i.e., dummy pressure chambers, on both ends in an arrangement direction of the plurality of pressure chambers arranged in one or two rows.
Recently, there have been various attempts to realize a printing at high speed and with high picture quality, in one of which pressure chambers are arranged in a matrix, instead of in an in-line shape. Also in this case, similarly to the above-described ink-jet head in which the pressure chambers are arranged in the in-line shape, there may be caused a problem that ink ejecting characteristics of the pressure chambers vary depending on three-dimensional structures surrounding the respective pressure chambers, which differ from each other due to positions in a group of pressure chambers in which a plurality of pressure chambers are arranged in a matrix.
Thus, an objective of the invention is to provide an ink-jet head capable of reducing variance in ink ejecting characteristics depending on positions in a group of pressure chambers formed with a plurality of pressure chambers arranged in a matrix to neighbor each other.